Initial commit

.gitignore

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+*.gem
+*.rbc
+.bundle
+.config
+.yardoc
+Gemfile.lock
+InstalledFiles
+_yardoc
+coverage
+doc/
+lib/bundler/man
+pkg
+rdoc
+spec/reports
+test/tmp
+test/version_tmp
+tmp

Gemfile

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+source 'https://rubygems.org'
+
+gemspec

README.md

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+# Ruby Decorators
+
+#### Ruby method decorators inspired by Python.
+
+## Installation
+
+Add this line to your application's Gemfile:
+
+    gem 'ruby_decorators'
+
+And then execute:
+
+    $ bundle
+
+Or install it yourself as:
+
+    $ gem install ruby_decorators
+
+## Usage
+
+```ruby
+  # TODO
+```
+
+## License
+
+Copyright (c) 2012 [Fred Wu](http://fredwu.me/)
+
+Licensed under the [MIT license](http://fredwu.mit-license.org/).

Rakefile

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+require "bundler/gem_tasks"
+
+require 'rake/testtask'
+
+
+Rake::TestTask.new do |t|
+  t.libs.push 'lib'
+  t.test_files = FileList['spec/**/*_spec.rb']
+  t.verbose = true
+end
+
+task :default => :test

lib/ruby_decorator.rb

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+class RubyDecorator
+  def self.+@
+    RubyDecorators::Stack.decorators << self
+  end
+
+  def +@
+    RubyDecorators::Stack.decorators << self
+  end
+end

lib/ruby_decorators.rb

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+require "ruby_decorators/version"
+require "ruby_decorator"
+require "ruby_decorators/stack"
+
+module RubyDecorators
+  def method_added(method_name)
+    @decorated_methods ||= []
+
+    return if RubyDecorators::Stack.decorators.empty?  ||
+              method_name.to_s =~ /__undecorated_/     ||
+              @decorated_methods.include?(method_name)
+
+    current_decorator = RubyDecorators::Stack.decorators.pop
+    method_visibility = detect_method_visibility(method_name)
+
+    class_eval <<-RUBY_EVAL, __FILE__, __LINE__ + 1
+      alias_method :__undecorated_#{method_name}, :#{method_name}
+
+      @__decorators ||= {}
+      @__decorators["#{method_name}"] = current_decorator
+
+      #{method_visibility}
+      def #{method_name}(*args, &blk)
+        decorator = #{current_decorator}.new
+        decorator ||= self.class.instance_variable_get(:@__decorators)["#{method_name}"]
+
+        if args.any?
+          decorator.call(self.send :__undecorated_#{method_name}, *args, &blk)
+        else
+          decorator.call(self.send :__undecorated_#{method_name}, &blk)
+        end
+      end
+    RUBY_EVAL
+
+    @decorated_methods << method_name
+  end
+
+  private
+
+  def detect_method_visibility(method_name)
+    if private_method_defined?(method_name)
+      :private
+    elsif protected_method_defined?(method_name)
+      :protected
+    else
+      :public
+    end
+  end
+end

lib/ruby_decorators/stack.rb

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+module RubyDecorators
+  class Stack
+    def self.decorators
+      @decorators ||= []
+    end
+  end
+end

lib/ruby_decorators/version.rb

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+module RubyDecorators
+  VERSION = "0.0.1"
+end

ruby_decorators.gemspec

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+# -*- encoding: utf-8 -*-
+lib = File.expand_path('../lib', __FILE__)
+$LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
+require 'ruby_decorators/version'
+
+Gem::Specification.new do |gem|
+  gem.name          = "ruby_decorators"
+  gem.version       = RubyDecorators::VERSION
+  gem.authors       = ["Fred Wu"]
+  gem.email         = ["ifredwu@gmail.com"]
+  gem.description   = %q{Ruby method decorators inspired by Python.}
+  gem.summary       = gem.description
+  gem.homepage      = ""
+
+  gem.files         = `git ls-files`.split($/)
+  gem.executables   = gem.files.grep(%r{^bin/}).map{ |f| File.basename(f) }
+  gem.test_files    = gem.files.grep(%r{^(test|spec|features)/})
+  gem.require_paths = ["lib"]
+
+  gem.add_development_dependency 'rake'
+  gem.add_development_dependency 'pry'
+  gem.add_development_dependency 'minitest'
+end

spec/ruby_decorators_spec.rb

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+require File.expand_path(File.dirname(__FILE__) + '/spec_helper')
+
+describe RubyDecorators do
+  class DummyDecorator < RubyDecorator
+    def call(this)
+      'I should never be called'
+    end
+  end
+
+  class Batman < RubyDecorator
+    def call(this)
+      this.sub('world', 'batman')
+    end
+  end
+
+  class Catwoman < RubyDecorator
+    def initialize(*args)
+      @args = args.any? ? args : ['catwoman']
+    end
+
+    def call(this)
+      this.sub('world', @args.join(' '))
+    end
+  end
+
+  class DummyClass
+    extend RubyDecorators
+
+    attr_reader :greeting
+
+    def initialize
+      @greeting = 'hello world'
+    end
+
+    def hello_world
+      @greeting
+    end
+
+    +Batman
+    def hello_public
+      @greeting
+    end
+
+    +DummyDecorator
+    def hello_void
+      @greeting
+    end
+
+    +Batman
+    def hello_with_args(arg1, arg2)
+      "#{@greeting} #{arg1} #{arg2}"
+    end
+
+    +Catwoman
+    def hello_catwoman
+      @greeting
+    end
+
+    +Batman
+    def hello_with_block(arg1, arg2, &block)
+      "#{@greeting} #{arg1} #{arg2} #{block.call if block_given?}"
+    end
+
+    +Catwoman.new('super', 'catwoman')
+    def hello_super_catwoman
+      @greeting
+    end
+
+    protected
+
+    +Batman
+    def hello_protected
+      @greeting
+    end
+
+    private
+
+    +Batman
+    def hello_private
+      @greeting
+    end
+  end
+
+  subject { DummyClass.new }
+
+  it "#hello_world" do
+    subject.hello_world.must_equal 'hello world'
+  end
+
+  describe "a simple decorator" do
+    it "decorates a public method" do
+      subject.hello_public.must_equal 'hello batman'
+    end
+
+    it "decorates a protected method" do
+      subject.send(:hello_protected).must_equal 'hello batman'
+      lambda { subject.hello_protected }.must_raise NoMethodError
+    end
+
+    it "decorates a private method" do
+      subject.send(:hello_private).must_equal 'hello batman'
+      lambda { subject.hello_private }.must_raise NoMethodError
+    end
+
+    it "decorates a method with args" do
+      subject.hello_with_args('how are', 'you?').must_equal 'hello batman how are you?'
+    end
+
+    it "decorates a method with a block" do
+      subject.hello_with_block('how are', 'you') { 'man?' }.must_equal 'hello batman how are you man?'
+    end
+  end
+
+  describe "a decorator with args" do
+    it "decorates without any decorator args" do
+      subject.hello_catwoman.must_equal 'hello catwoman'
+    end
+
+    it "decorate a simple method" do
+      subject.hello_super_catwoman.must_equal 'hello super catwoman'
+    end
+  end
+end

spec/spec_helper.rb

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+require 'minitest/autorun'
+require 'minitest/spec'
+require 'pry'
+
+require File.expand_path('../../lib/ruby_decorators', __FILE__)